1. Field of the Invention
The present invention relates to a recording tape cartridge accommodating, within a case, a single reel on which is wound a recording tape, such as a magnetic tape or the like, which is used as a recording/playback medium mainly of computers or the like.
2. Description of the Related Art
Conventionally, magnetic tape cartridges have been known in which a magnetic tape, which is used as a data recording/playback medium of a computer or the like, is wound on a single reel, and the reel is accommodated in a case. A leader member, such as a leader pin, a leader tape, or a leader block, is provided at the distal end of the magnetic tape. A pull-out means provided at a drive device pulls the leader member out from an opening of the magnetic tape cartridge, and winds the magnetic tape, which is fixed to the leader member, onto a take-up reel of the drive device.
A reel gear is formed in an annular form in the center of the bottom surface of a reel which emerges from an open hole formed in the bottom surface of the magnetic tape cartridge. Due to a driving gear, which is provided at a rotating shaft of the drive device, meshing with this reel gear, the reel is driven to rotate. By rotating the reel of the magnetic tape cartridge and the take-up reel of the drive device synchronously, data can be recorded onto the magnetic tape, and data recorded on the magnetic tape can be played back.
Such a magnetic tape cartridge requires little space for storage, and a large amount of information can be recorded thereon. The position of the opening and the type of the door which opens and closes the opening differ for each type of leader member. For example, in the case of a leader pin, as shown in FIG. 7, an opening 68 for pulling out of a leader pin 60 is formed in a side wall 64 of a case 62. The opening 68 is opened and closed by a door 66 which slides in the direction of loading the magnetic tape cartridge into a drive device (the direction of arrow P) and the direction opposite thereto.
A pair of top and bottom pin holding portions 70, which hold the leader pin 60 when the magnetic tape cartridge is not being used (is being stored or the like) are provided at the inner side of the opening 68 of the case 62. As shown in FIG. 8, the pin holding portions 70 are concave portions which are substantially semicircular as seen in plan view, and respective one portions of the pin holding portions 70 are open so that the leader pin 60 can enter therein and exit therefrom. Both end portions of the leader pin 60, which is in a state of standing upright, are inserted into these concave portions (the pin holding portions 70). An anchor spring 72 is disposed in a vicinity of the pin holding portions 70 (the opening 68). Distal end portions (free end portions) 72B, which have been forked in two, of the anchor spring 72 push the upper and lower ends of the leader pin 60 toward the inner sides of the pin holding portions 70. In this way, the leader pin 60 does not fall out from the pin holding portions 70.
When the leader pin 60 enters into and exits from the pin holding portions 70, the distal end portions 72B of the anchor spring 72 elastically deform appropriately so as to permit movement of the leader pin 60. Conventionally, a proximal portion 72A of the anchor spring 72 is held by spring holding portions 74 in a state in which the proximal portion 72A closely contacts an inner surface 63A of a front wall 63 of the case 62 which front wall 63 faces in the direction of arrow P. Providing the anchor spring 72 in this state is preferable because it is easy to assemble the anchor spring 72 into the case 62, and the anchor spring 72 can be assembled stably.
However, because the opening 68 is formed at the end portion of the front wall 63 at which the anchor spring 72 is provided, this end portion is a free end and is a relatively weak portion. Even if an attempt is made to provide some type of reinforcing means thereat, it is difficult to ensure the space therefor because the reel 76 must be accommodated and the spring holding portions 74 must be provided.